The invention relates to tape transport systems of the type in which the take-up reel of a self-threading magnetic recording tape is driven by surface engagement with a rotating capstan; and it relates more particularly to a safety arrangement in such a system by which accidental spillage or jam-up of the tape during the threading operation is prevented.
In order to render the thin magnetic tape self-threading, a thicker but flexible leader having teeth on its edges is typically attached to the forward end of the tape. As the supply reel in the self-threading operation begins to be rotated by the driven capstan, the forward end of the leader is peeled off this tape reel by a peeling device and the leader is then advanced--usually past a guide partially surrounding the capstan and past one or more magnetic heads--towards the interface between the capstan and the take-up reel. Normally, after the tip of the leader has been gripped in the nip between the capstan and the take-up hub, the teeth of the leader securely grip the sides of the take-up hub near its periphery and the leader, followed by the tape itself, is wound on the take-up hub. A self-threading arrangement of the kind just described has been disclosed, for example, in U.S. Pat. No. 3,955,777 to D. L. Burdorf. Alternative designs of self-threading leaders of a type which may be utilized with the present invention are disclosed in U.S. Pat. No. 3,773,276 to K. E. Ganske and U.S. Pat. No. 3,836,094 to A. J. Hollingsworth, both of which also have gripping teeth, and U.S. Pat. No. 3,370,803 to C. W. Newell which uses an adhesive surface to detachably secure the leader to the tape pack and take-up reel.